1. Field of the Invention
This invention relates in general to nestable and extendable pouring spouts for containers and in particular to such spouts having a venting means for reducing pulsations in the outflowing liquid.
2. Description of the Prior Art
There are a number of prior known nestable and extendable pouring spouts. Representative examples are shown in the following U.S. Pat. Nos.: 2,561,596 to Rieke, July 24, 1951; 2,565,699 to Rieke, Aug. 28, 1951; 2,661,128 to Rieke, Dec. 1, 1953; 2,895,654 to Rieke, July 21, 1959; 3,040,938 to Smith, June 26, 1962; 3,250,428 to Rieke, May 10, 1966; 3,604,740 to Summers, Sept. 14, 1971; 3,613,966 to Summers, Oct. 19, 1971; 3,804,305 to Rieke, Apr. 16, 1974; and 4,295,583 to Schurr, Oct. 20, 1981.
Of the above listed patents, Nos. 3,040,938 and 4,295,583 relate particularly to vented spouts.
In many cases a smooth outflow of liquid from the spout of a container is particularly important. Examples are where it is desired to decant a precise amount of liquid from a large stock container into a smaller container or where the liquid is corrosive or toxic and splashing must therefore be avoided.
Smooth, pulsation-free outflow may be obtained with a conventional spout by carefully controling the angle of the spout with regard to the fluid level in the container so that the spout never flows full, thereby maintaining an air passageway through the spout into the container. One disadvantage of this method is that the required degree of control is often difficult to maintain, especially where the container is heavy. Another disadvantage is that only a fraction of the cross sectional area of the spout is available for fluid outflow when the container is near full, thus increasing the time necessary to decant the liquid.
As a solution to the aforementioned problems, prior nestable and extendable spouts have been fitted with venting devices for maintaining an air passageway through the spout regardless of the angle of pouring, enabling venting of the container even though the opening of the container is completely submerged (see Smith, No. 3,040,938 and Schurr, No. 4,295,583). These prior venting devices are essentially tubes mounted concentrically within the neck of the spout so as to form an annular air space between the tube and the neck. The base of the tube is fitted with a flange having a plurality of small peripheral channels, which flange is drawn up against the base of the spout when the spout is in its extended orientation. In this orientation, air may enter the container through the annular space and the peripheral channels while the fluid exits through the central tube.
Although the venting devices exemplified in Smith ('938) and Schurr ('583) function well, they have non-functional disadvantages associated with their structure. For instance, the venting device must be manufactured as a separate piece which is then mounted within the neck of the spout and secured thereto by welding or adhesive. This is a relatively expensive manufacturing process. Additionally, the venting device adds to the overall axial length of the spout when it is in its nested orientation, thus increasing the handling, packaging and shipping costs of such a spout.
It would be desirable to provide a nestable and extendable pouring spout with a self contained venting means which may be inexpensively manufactured and which maintains the compact configuration of such spouts.